小球碰撞(多线程)

package main;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;

public class Ball {
	private static final int XSIZE = 15;
	private static final int YSIZE = 15;
	private double x = 0;
	private double y = 0;
	private double dx = 1;
	private double dy = 1;
	public Ball()
	{
		x = Math.random() * (450 - XSIZE);
		y = Math.random() * (350 - YSIZE); 
		
	}
	public void move(Rectangle2D bounds)
	{
		x += dx;
		y += dy;
		if (x < bounds.getMinX())
		{
			x = bounds.getMinX();
			dx = -dx;
		}
		if (y < bounds.getMinY())
		{
			y = bounds.getMinY();
			dy = -dy;
		}
		if (x + XSIZE > bounds.getMaxX())
		{
			x = bounds.getMaxX() - XSIZE;
			dx = -dx;
			
		}
		if (y + YSIZE > bounds.getMaxY())
		{
			y = bounds.getMaxY() - YSIZE;
			dy = -dy;
			
		}
	}
	
	public Ellipse2D getShape()
	{
		return new Ellipse2D.Double(x, y, XSIZE, YSIZE);
		
	}
	
	

}

package main;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.ArrayList;
import java.awt.Dimension;
import javax.swing.JPanel;

public class BallPanel extends JPanel
{
	private static final int DEFAULT_WIDTH = 450;
	private static final int DEFAULT_HEIGHT = 350;
	//Ball ball;
	ArrayList BallList;
	public BallPanel()
	{
		BallList = new ArrayList();
	}
	public Ball add()
	{
		Ball tmp = new Ball();
		BallList.add(tmp);
		return tmp;
	}
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		Graphics2D g2 = (Graphics2D) g;
		for (Ball ball : BallList)
		{
			g2.fill(ball.getShape());
		}
		
		//ball.move(getBounds());
	}
	public Dimension getPreferredSize()
	{
		return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
	}

}
class BallThread extends Thread
{
	BallPanel panel;
	Ball ball;
	public BallThread(Ball ball, BallPanel panel)
	{
		this.ball = ball;
		this.panel = panel;
		
	}
	
	public void run()
	{
		
		while (true)
		{
			
			ball.move(panel.getBounds());
			try
			{
				Thread.sleep(1);
			}
			catch (InterruptedException ex)
			{
				ex.printStackTrace();
			}
			panel.repaint();
		}
	}
}

package main;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.EventQueue;

public class BallFrame extends JFrame 
{
	BallPanel panel;
	public BallFrame()
	{
		panel = new BallPanel();
		add(panel, BorderLayout.CENTER);
		JButton button1 = new JButton("start");
		JPanel ButtonPanel = new JPanel();
		
		
		button1.addActionListener(new ActionListener()
				{

					@Override
					public void actionPerformed(ActionEvent arg0) {
						// TODO Auto-generated method stub
						BallThread thread = new BallThread(panel.add(), panel);
						thread.start();
						
						
					}
			
				}
		);
		ButtonPanel.add(button1);
		add(ButtonPanel, BorderLayout.SOUTH);
		
				
	}
	public static void main(String[] args)
	{
		EventQueue.invokeLater(new Runnable()
				{

					@Override
					public void run() {
						// TODO Auto-generated method stub
		
						BallFrame frame = new BallFrame();
						frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
						frame.setSize(500, 500);
						frame.setVisible(true);
		
					}
			
				}
		);
		
		
		
	}
	

}